Dumbbell support structure



FIG. 1 is a front isometric view of a dumbbell support structure of the present invention, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design;

FIG. 2 is a front elevation view of the dumbbell support structure of FIG. 1, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design;

FIG. 3 is a rear view of the dumbbell support structure of FIG. 1, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design;

FIG. 4 is a right elevation view of the dumbbell support structure of FIG. 1, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design;

FIG. 5 is a left elevation view of the dumbbell support structure of FIG. 1, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design;

FIG. 6 is a top view of the dumbbell support structure of FIG. 1, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design; and,

FIG. 7 is a bottom view of the dumbbell support structure of FIG. 1, wherein the broken line structure is provided to illustrate environmental structure that forms no part of the claimed design. 

The ornamental design for a dumbbell support structure, as shown and described. 